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Brain changes during adolescence

During adolescence, the brain undergoes significant changes. The prefrontal cortex, responsible for decision-making and long-term goals, matures. The limbic system, which regulates emotions and hormones, also develops. Additionally, the corpus callosum, connecting brain hemispheres, alters, impacting language learning. Lastly, increased myelination speeds up neuron communication, and synaptic pruning strengthens frequently used brain connections. Created by Brooke Miller.

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  • leaf green style avatar for user Sisay1
    I think it has a lot to do with cultural backgrounds and parents' ways of showing discipline and bonding while teens were still young. Some cultures of the world, in which kids don't talk back to parents, you never witness door slams and kids screaming at parents. All adolescents in the world do have a growing brain and yet in some cultures they turn out to be loving and responsible leaders and in other cultures they turn out to have negative behaviors.
    (5 votes)
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    • piceratops ultimate style avatar for user antlunyov
      Just because they have no external behavior doesn't mean their cognitions or emotions don't reflect these changes. You're thinking about this like a behaviorist, not a biologist.

      Yes, other cultures don't have as much teen rebelliousness... on the surface. However, even great apes show similarly rebellious thoughts and patterns, and they are our closest ancestor.

      My point is, just because an adolescent doesn't slam doors doesn't mean they don't get impulses to do so. It's the impulses that are universal, not the behavior.
      (30 votes)
  • blobby green style avatar for user Konyin  Adewumi
    I totally think developmental research should have a role! I know this video was posted years ago but it is interesting to think about the rise in media around police brutality and its impact on children/ children of color. This video, combined with the physical development video (which I would like to point out that looking like a adult plays a huge role in how you are treated by the justice system) are just drops in a sea of information that shows that children shouldn't be tried as adults. Ever. They just ARENT adults. If they dont stick to our definitions, then whats the point of having them. If I am not an adult, then I should not be allowed to be treated as an adult. Which includes prosecution, sexual interaction, holding children to impossible standards, etc.
    (3 votes)
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  • leafers ultimate style avatar for user Constantine
    I thought the limbic system contained the amygdala, hippocampus, and septal nuclei? While the hypothalamus resided in the forebrain along with the limbic system, but is categorized separately.
    (0 votes)
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    • piceratops ultimate style avatar for user Sofia Hu
      Which structures in the brain should be considered part of the limbic system is actually still a debated subject, especially since so many structures interact with each other in processes like emotion and behavior. You are right that the amygdala, hippocampus, and septa nuclei are part of the limbic system, but structures like the nucleus accumbent, piriform cortex, hypothalamus and thalamus are also considered part of the limbic system.

      I use the mnemonic "Hippo HAT" to remember what is in the limbic system — hippo for hippocampus, and HAT for hypothalamus, amygdala, thalamus. Of course, this doesn't include all of the limbic system structures.
      (6 votes)
  • blobby green style avatar for user mysturi0us
    Shouldn't the prefrontal cortex located closer to the central gyrus? The part that is shaded is the frontal cortex...right?
    (0 votes)
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  • blobby green style avatar for user kadence_fox
    MLA Ciation fro video
    (1 vote)
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  • blobby green style avatar for user korey schneider
    Charging criminals based on stage of brain development raises so many questions when it comes to being truly judicious. Although development (aka incomplete structure) may be a cause to charge adolescents differently than adults, there can be significant variation in brain physiology between adult individuals. (Examples and details are easy to find on this topic)

    Maybe we should start every criminal trial with a brain scan to measure volume of relevant areas such as the PFC and Hypothalamus. We can input these data findings into an algorithm that will create a probabilistic model for likelihood of future criminal behavior and likelihood of successful behavioral rehabilitation. This algorithm can then create a suggested sentence and/or parole program. This can also be used for adolescents to assess level of brain development and compare that to a standardized adult model.
    Just a thought.
    (1 vote)
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  • piceratops seed style avatar for user Hazel
    What are the functions of the Corpus Callosum?
    (1 vote)
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Video transcript

- [Instructor] When we think about changes that happen during puberty, we usually think about changes that happen to the body. Things like the development of secondary sex characteristics or changes in height or an increase in body hair. But those aren't the only changes that happen. There are actually a lot of changes that happen to the brain as well. Here I have an image of a brain. This is what you would see if you looked at the side of the brain. Here is the front towards the face. Here's the back. And then over here, I have another brain and this brain is sliced in half. This brain is sliced right down the middle. These two brains are facing each other. So here's the front. And then here's the back of this one. One of the major changes that we see during adolescence is the development of the frontal lobe, particularly the prefrontal cortex. I'll roughly indicate where on the brain that is. This is the area of the brain that is responsible for what scientists call higher order cognition. Things like thinking about the future, and planning, and decision making. And also the ability to inhibit certain behaviors and focus on longterm goals. This part of the brain doesn't really stop maturing until our early twenties. Because it is still developing during the teenage years, because it isn't fully developed. this might help to explain why teenagers sometimes show poor judgment. Another area of the brain that continues to develop during adolescence is the limbic system. This includes a number of different brain structures. This image isn't really the best way to view them because a lot of the structures are on either side of the midline. Even so, I want to point out about where they are in the brain. One structure included in the limbic system is the amygdala, which would be about here. This is the part of our brain that's responsible for emotions and emotional responses. It also includes the hypothalamus, which is here and let me pick a slightly different color for that. This part of the brain regulates a surprising number of things. But in particular, I wanna focus on its role concerning the endocrine system or the hormone system in our bodies. To be clear, the limbic system includes a bunch of other structures as well, but I really wanna focus on these two, because in combination with the prefrontal cortex, which helps to regulate our emotions, the fact that these structures are still developing during the teenage years might help to explain why teenagers can sometimes be moody, why they might sometimes have emotional outbursts, like yelling at their parents and stomping out of the room and slamming the door. While I think that this is kind of funny and while it kind of makes me want to roll my eyes when teenagers act out, this does actually have some really important legal implications, like whether or not we should be able to charge teenagers like adults when they commit certain crimes. This is a question that I put to you. Should teenagers get the same treatment as adults if they commit the same crimes? Should they be able to be sentenced to death or to life in prison for acts that they commit prior to turning 18? Do you think that this is a good boundary? Are crimes committed one month before someone's 18th birthday really different from crimes that they commit one month after? Where should this boundary be? How should we define adulthood? These are really difficult and serious questions and it's really not clear what role developmental research has in solving these problems or if it should even have a role at all. Putting that very serious question aside, another area of the brain that changes during adolescence is the corpus callosum, which you can see here. This is the area of the brain that connects our left and right hemispheres. There are a number of things that change about the structure during adolescence. But in particular, I really wanna focus on the changes to connections that are associated with language and language learning. These connections grow before and during puberty but this growth stops soon afterwards. This might help to explain why learning a second language is so much easier in childhood as compared to adulthood. So we see changes to those specific brain areas but there are also other more global changes that are happening in the brain during this period or changes that are happening throughout the brain. One thing that we see during this period is an increase in myelination, especially in the areas that are associated with higher order functioning. To quickly review, this is a neuron and neurons communicate with each other by sending signals down these long axons. Myelin is a fatty tissue that covers the axons of neurons and helps to increase the speed at which the neurons can communicate. Faster communication between neurons means faster communication between brain areas. This can help explain why adolescents are able to process information faster than children. Another thing that we see during this time period is that there's an increase in brain volume during early adolescence and then this shrinks during late adolescence. This suggests that adolescence is a period of synaptic pruning or cutting weak connections in the brain. So this is your body literally breaking down connections between neurons. You might initially think that this is a bad thing, but this pruning is actually really good and it's really important because it allows the body to focus energy and resources on the connections that are used most. A kind of scary implication of this is that what we do during our teenage years might be literally shaping our brains for the rest of our lives. But there's kind of a use it or lose it principle at work here. So if we spend our free time reading, or playing sports, or focusing on academics, and having good time management skills, then that's what's going to be reinforced. The parts of the brain that are responsible for those behaviors are physically going to be strengthened. But if we spend most of our time watching TV and sitting on our couch and procrastinating, that's what's going to be strengthened instead.